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When to plant Eggplant in Kankakee County, IL

In Kankakee County, plant Eggplant in spring between April 27 and May 18, once soil temps hold above 50°F. Kankakee County's last frost averages April 20, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 65–85 days before the first frost on October 14.

When to Plant Eggplant in Kankakee County, IL

Eggplant
Kankakee County, Illinois Zone 5b August

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Avg. last frost April 20
Avg. first frost October 14
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Bring in the eggplant

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Get ahead of September
  • First harvests: eggplant

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Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.

Kankakee County, Illinois is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.

At an elevation of 1,113 feet, Kankakee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Eggplant during the growing season.

Kankakee County, IL (Zone 5b) Moderate season
177 days
Last Spring Frost April 20
177 growing days
First Fall Frost October 14

Kankakee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Eggplant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 4 Transplant: Apr 29 🍅 Harvest: Jul 8 – Sep 9
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Feb 9 Transplant: May 4 🍅 Harvest: Jul 13 – Sep 14
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Feb 28 Transplant: May 23 🍅 Harvest: Aug 1 – Oct 3

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Kankakee County

How your county's soil matches Eggplant's growing requirements.

Soil pH

Your soil pH (6.1–6.8) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Kankakee County is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) — Eggplant will thrive.

How to Plant Eggplant

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Eggplant

3
successive plantings in your 177-day season

Sow every 7.4 weeks. Last sowing by Jul 21 to harvest before frost.

Eggplant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 477 gal / 100 sq ft

Monthly Watering Guide for Eggplant

Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Eggplant Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.8" 3.4" 1.4" 💧 Light watering
May 4.8" 4.3" 0.5" 💧 Light watering
Jun 4.8" 3.7" 1.1" 💧 Light watering
Jul 4.8" 3.6" 1.2" 💧 Light watering
Aug 4.8" 3.7" 1.1" 💧 Light watering
Sep 4.8" 2.8" 2" 💧 Light watering
Oct 4.8" 2.7" 2.1" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Kankakee County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Eggplant Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Eggplant needs ~1,031 GDD — county provides 2,433 GDD Excellent fit

Eggplant Planting Timeline — Kankakee County, IL

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest July 13 Jul 13 – Sep 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

177 days in Kankakee County

Growing Tips for Eggplant in Kankakee County

Direct sow Eggplant outdoors after April 20 in Kankakee County when soil has warmed and frost danger has passed.

Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Eggplant in Kankakee County, IL?

Kankakee County is in Zone 5b with an average last frost of April 20. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kankakee County, IL?

Kankakee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 14.

When should I plant Eggplant in Kankakee County, IL?

In Kankakee County, IL, plant Eggplant after the last frost (around April 20) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Kankakee County, IL for Eggplant?

Kankakee County sits in USDA Zone 5b. Eggplant grows reliably in zones 5a through 11b, so it's a good fit here.

Can Eggplant grow in Kankakee County's climate?

Yes — Eggplant grows well in Kankakee County's temperate climate. Kankakee County averages a 177-day frost-free season, with last frost around April 20 and first frost around October 14.

🌱

Your Kankakee County Garden Planner — Free

A 22-page printable planner built for Kankakee County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kankakee County, IL. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.